Power circuit portions used in a rotating electrical machine are formed in modules phase by phase and the bottom surface of each module is bonded to a heat sink. PTL 1 discloses a configuration, according to which each bonding surface is flat and formed of a single metal plate. Herein, neither the bonding surface is isolated from the heat sink, nor waterproof treatment is applied between the back surface and the heat sink.
PTL 2 discloses a configuration, according to which the power circuit portions are formed of mold-encapsulated modules
Herein, a plurality of modules are fixed to a disc-like heat sink with an insulating adhesive and all the modules on the heat sink are potted with encapsulation resin.